Interference mitigation is a key challenge in improving the capacity of future wireless networks. In a densely deployed and interference-limited network, an effective way to mitigate interference is through power control. The successful implementation of power control is, however, also dependent on its algorithmic complexity, the hardware limitations of the wireless front-end, and the ability to integrate power control with system-level operations, such as scheduling.
The use of power control for interference mitigation is of particular interest for wireless backhaul networks, which are deployed as a means to increase the network throughput for areas with high data traffic demand.
Power optimization in wireless networks can significantly improve the network wide performance, namely, throughput and fairness, in an interference-limited radio environment. Power optimization is usually through a maximization of the network wide sum utility. A -known utility function choice that improves both throughput and fairness is the sum of the logarithm of the long-term average data rate. However, optimization based on the exact form of this utility function requires continual updates of a measured average data rate of each network link and therefore, continual re-evaluation of the optimum power settings of each link, since this rate is dependent on the data traffic.
The classical problem of maximizing the log of long-term average rates often requires frequent updates of the found solutions, so as to adapt the problem to the changes in channel and traffic conditions. Further, classical solutions often involve additional iterations between scheduling and power control, which increases the problem computational complexity.
An iterative approach to joint power control and scheduling is disclosed, for example, in the above referenced, related co-pending U.S. patent application Ser. No. 13/463,478, entitled “Interference Mitigation with Scheduling and Dynamic Power Spectrum Allocation for Wireless Networks” by Dahrouj et al., and in PCT patent publication No. WO/2011/037319, published Mar. 31, 2011, by T. Kwon et al., entitled “Method and Device for User Scheduling and Managing Transmit Power in a Communication System” Other references that discuss scheduling and power control include: S. G. Kiani and D. Gesbert, entitled “Optimal and Distributed Scheduling for Multicell Capacity Maximization” IEEE Trans. Wireless Commun., Vol. 7, No. 1, pp. 288-297, January 2008″; L. Venturino, N. Prasad, and X. Wang, entitled “Coordinated Scheduling and Power Allocation In Downlink Multicell OFDMA Networks,” IEEE Trans. Veh. Technol., Vol. 6, No. 58, pp. 2835-2848, July 2009; and A. L. Stolyar and H. Viswanathan, entitled “Self-Organizing Dynamic Fractional Frequency Reuse For Best-Effort Traffic Through Distributed Intercell Coordination,” in INFOCOM, April 2009.
The above solutions involve a complex process of iterations, where delays and changes in channel conditions impose additional practical challenges.
Thus, there is a need for alternative systems and methods for power control, and in particular, practically feasible methods for interference management and load balancing, which provide low computational complexity and fast convergence.